Method of destroying sewage



Oct. 10, 1939. H. H. MORETON METHOD OF DESTROYING SEWAGE Filed Aug. 2,1935 2 Sheets-Sheet 1 Oct. 10, 1939. H. H. MORETON METHOD OF DESTROYINGSEWAGE Filed Aug. 2, 1935 4 2 Sheets-Sheet 2 Tjjji: 75

55 the chamberl0.

Patented Oct. 10, 1939 PATENT OFFICE 2,175,300 I METHOD OF DESTROYING'SEWAGE Henry H. Moreton, Santa Monica, Calif. Application August 2,1935, Serial No. 34,481

8 Claims.

This invention is a method and apparatusfor effecting completedestruction of sewage.

The effective destruction of sewage without soil or water pollution haslong been a serious probe lem. In fact, attempts heretofore made tophysically destroy sewage have met with indiiferent success from thestandpoint of practical economy, and convenience and complete sanitarysafety in handling, and so that at the present time, the so-calledbacterial systems are considered the safest and most desirable methodsfor municipal installations. A system of the last-mentioned type,however, involves the installation of apparatus which must be spreadover a considerable area, requires a very large investment to meet theinitial cost of installation, and is more or less expensive to operate.

One of .the objects of the invention is to pro-j vide for complete andeconomical physical de-' struction of sewage by incineration, wherebypractically no residue is left, so that thepossi bility of either soilor water pollution is reduced to the absolute minimum. A further objectis to provide for complete incineration of sewage in such manner thatthe discharge of objectionable and offensive odors, smokes and gasesinto the surrounding atmosphere is prevented. A further object is topro-vide a system of low installation cost and highly economicoperation, capable of providing for initial dehydration of thesewage andsubsequent complete incineration in a continuous process. A furtherobject is to employthe' caloric values inherent to the sewage beingtreated, to assist in the incineration of the material being treated,after its dehydration.

The invention will be hereinafter fully set. forth and particularlypointed out in the claims.

In the accompanying drawings:

Figure 1 is a vertical elevation more or less diagrammatic in character,illustrating an apparatus constructed in accordance with the invention,certain parts being shown in section. Figure 2 is a detail sectionalview of a portion of one of the rotatable furnaces. Figure 3 is a sideelevation diagrammatically illustrating a modification.

Referring to the drawings, I designates a combined dehydrator andincinerator, which consists of a relatively long cylindrical chamber In,rotatively supported in a longitudinally inclined position, a well knownmanner, by suitable bearings ll. may be efiected by any suitable means,such as a gear l2 engaging a gear-ring l3, which encircles The higherend of said cham- Rotation of the cylindrical chamber berlfl' projectsinto a receiving chamber l4, through the top of which extends an inletchute l6.f a

- The open lowerend of the cylindrical chamber It extends into a burnerbox 20, into which is projectedone -or more burners 2| for gas, oil, orthe like,,the delivery ends of the burners being directed axially towardthe incinerator I, in such manner as to project the flame into the openlower end of the latter. The burner casing rests upon a suitableplatform 22, onto which the chamber [0 deposits the material which isdischarged from the lower end thereof, said platform, having a chute 23which communicates with theinterior of a mixing apparatus 24, operatedby'a suitable motor 25. The mixing apparatusfz l maybe of any suitableor desired construction, such as'the common type of apparatus usuallyemployed for, mixing concrete. Any

gases .whi ch' may accumulate in the top of the 20 mixer are drawn outby blower l5 and delivered to theburner box 20. A flue 26 connects thereceiving chamber with" an offset chamber a of a "lihe"mixer .j2 ldischarges into the inlet chute 5 incinerator I' consists of arelatively long cylin- 30 drical chamber lza which is rotativelysupported in a lo'ngitudinallyinclined position, by suitable bearings Ila. Rotation of said cylinder Illa. may be-also'efiected by means of agear [211 engaging the gear-ring I3w, encircling the cylinder Illa. A 35flue '2 60. connects the receiving chamber l4a with offset chamber a. ofthe stack 3. The incineratorI'; at its lower end, discharges into aburner box 23a, into which is projected one or more burners 2 la,similar to the burners 2i, the deliv- 40 ery ends of the burners beingdirected axially toward the incinerator'I', in such manner as to projectthe flame into the open lower end of the latter. The burner casing Ziaalso rests upon a suitable platform 22a, onto which said chamber 45 Idischarges the 'materialwhich has been passed therethrough, saidplatform also having a chute 23a, which discharges into a second mixer24a, similar in every respect to the mixer 24, and

driven by a motor 25a, and similarly vented by 50 blower ltd.-

The mixer 240. may discharge into. a suitable storage bin or the like,but it is preferred to discharge'the same into the bottom of a conveyorpit 21, from which a'chain conveyor 28 will detributing chamber 28',adjacent the high end of incinerator I, from which material may be fedto the last-mentioned incinerator through the inlet chute I6. It will beobserved that each of the incinerators I and I is provided with anannular bafiie 29, which is spaced a short distance from the deliveryend of the chamber.

Located in a suitable position adjacent to the apparatus thus fardescribed is a suitable storage tank 30 for the sewage, preferably inthe form of sludge. Leading from the lower end of said tank is adischarge pipe 3|, which delivers the sludge to the pump 32, by whichthe sludge is delivered to the mixer 24 through a pipe 33. Also leadingfrom the tank 30 is a branch outlet pipe 31a connected to a second pump32a, which delivers sludge through a pipe 33a to the mixer 24a. Thepumps 32 and 320. are driven in suitable manner, as by a motor 34,

In operation, assuming the burners 2| and Zla are lighted and inoperation, an initial charge of sand or similar inorganic granularmaterial, capable of withstanding high temperature without fusing, isplaced in the pit 21. It is preferred to use good sharp silica sand.Sufiicient sand must be initially employed to insure a continuous streamof sand through all of the incinerators. The sand is elevated to thehopper 28' and introduced into the incinerator I through the chute i5,and the rotation of the cylinder ID will cause the sand to travel slowlydownwardly through said cylinder, so that it will receive a hightemperature due to the heat generated by the burners 2|. The burners aredirected toward the downwardly flowing material in a manner adapted toimpart a relatively high temperature to the sand, but the heat must beregulated so as to avoid fusing temperature, because fusing of the sandparticles would greatly impair the operation.

The apparatus will be primed for operation at the time that cylinder l0begins to discharge heated sand from the lower end thereof. As theheated sand is discharged from the incinerator I, it is delivered to themixer 24. Coincidentally with delivery of hot sand to the mixer,

the pump 32 is put into operation, so as to deliver sludge to the mixer24 for mixture with the heated sand. The sand and sludge are intimatelymixed until the sand particles are thoroughly coated with colloidalportions of the sewage constituents. The coated inorganic material isthen discharged into the high end of incinerator I. Because of therotation of the chamber Illa the coated material will be tumbled aboutand agitated, and caused to travel downwardly toward the burners Zia,thereby being caused to move through a heated space within which it issubjected to a gradually increasing temperature as it approaches saidburners. Therefore, almost immediately after the mixture enters theincinerator I, the temperature is sufficiently high to dehydrate thecoatings, and during the subsequent travel of the mixture thetemperature is sufficiently increased to ignite the dehydrated organicmaterial, but without fusing the refractory material, and incinerationof the organic constituent is completed by the time that the granularcarrier material reaches the discharge end of said chamber Ifla andimmediately before it is discharged into the mixer 24a. Due to theretarding action of the baffle 29, a constantly moving bed of fire backof the bafile is provided, with the result that complete combustiontakes place in this zone, to such an extent that there is 2,175,300 aliver the discharged material to an elevated dispractically no residualmatter left by the sewage, and the material discharged to the mixer 24ais practically the dried heated sand. As dehydration and incinerationtake place during the travel of the mixture, combustible gases are givenoff, which are ignited by the heat within the cylinder, thereby aidingin the combustion of the dehy drated coatings material. The products ofcombustion pass to the stack S through flue 26.

As the stream of sand is discharged from chamber Illa, it is deliveredto the mixer 24a, and at this time the pump 32a is put into operation,so as to supply sludge to the mixer 24a, as the latter receives the hotsand from said chamber lOa. Said sand and the new sludge are intimatelymixed and the sewage-coated refractory material is discharged into thepit 21. From this last position, the mixture of hot sand and sludge iselevated to the platform 28 and discharged into the incinerator Ithrough the chute 5, whereupon, the mixture travels through the chamberIn in such manner as to be subjected to the heat of the burners 2|, sothat dehydration takes place at the upper portion, and completecombustion takes place at the baffie 29, in the manner already describedin connection with the incinerator I, the products of combustion passingto the stack through chamber l6. In both instances the operation is socomplete that as dehydration takes place, the combustible gases willalso be ignited, thereby materially aiding in the destruction of odorsand smoke, as well as in the combustion of the sewage itself, the gasesof combustion which are carried to the stack being without noticeableodor. served that once the apparatus has been put into operation, thecycle is continuous and that the same batch of sand may be used over andover indefinitely as long as the heat is kept below the fusingtemperature. If desired, however, at the end of a cycle the sand thathas been used may be replaced with new sand, the old sand being treatedto a separating process of any desirable character, so as to remove anyforeign material which may possibly remain, so that the sand is renderedsuniciently pure for building purposes. Where a plant of smallercapacity will suifice, a single incinerator I may be employed in lieu ofthe plurality of incinerators illustrated in Figure 1. Such amodification is illustrated in Figure 3, in which the same type ofrotating cylinder lilb is employed, as heretofore described, the samebeing provided with the receiving chamber Mb, the burner chamber 20b andburners 2lb, rotation of the cylinder being effected in the manneralready described in connection with Figure 1. Material from the chamberIOb is discharged into a mixer 2%, which is vented by means of theblower I'Jb, and the mixture discharges through a spout 31 onto aconveyor C, which elevates the mixture to the chute I6b, so as to bedelivered into the chamber Mb. Sludge is supplied to the mixer throughthe pipe 331). The receiving chamber Mb is connected with an extensionat of the stack S by means of a flue 261).

In operation of the form disclosed in Figure 3, a charge of sand isfirst introduced through the chute lfib into chamber I 0b, and is heatedby the burners as it travels toward the lower end of said chamber. Thehotsand is then discharged into the mixer Web and mixed with sewagesludge in the manner already fully described, and the mixture isdeposited upon the conveyor, so that it Will be elevated and dischargedinto the chute l6b. Thereafter, the mixed sludge and hot sand From theforegoing, it will be obwill travel through the cylinder I 01), andduring this travel the sludge will first be dehydrated and thencompletely incinerated, so that the practically pure heated sand mayagain be discharged into the conveyor for another cycle. The foregoingcycle may be continued until the supply of sludge is exhausted.

As previously stated, any preferred type of mixer may be employed in theapparatus illustrated in the drawings, but in each instance it ispreferred to provide a structure similar to that shown in Figure 3, inwhich a baflle 35 depends from the top wall of the mixer to a positionwell below the normal liquid level in the mixture, so as to trap anygases and to allow them to escape into the upper part of the mixer,where they are vented in the manner already described. The mixture isforced outwardly from the mixer through the outlet opening 36 into thedischarge spout 31.

The advantages of the invention will be readily apparent to thoseskilled in the art to which it belongs. An important advantage is thatowing to the fact that the sand particles acquire coatings of thecolloidal constituents of the water content of the sludge during thepassage of the mixture through the incinerator, it is easy to so controlits passage that even dehydration and subsequent incineration areeffected. Therefore, after the apparatus is once put in operation lessheat is required at the burner end than would otherwise be required,thereby preventing fusing of the sand, so that as the sand leaves anincinerator, it may be immediately mixed with more sludge and returnedto another incinerator, and a continuous hot sand cycle is provided.Another advantage is that as the sludge is subjected to the heat, itwill first give off its moisture and later will be completelyincinerated, the combustible gases given off during these stages beingcapable of developing sufiicient B. t. us. to very materially aid in thedestruction of following sewage. Another advantage is that by using twoor more incinerators, one set above the other, and the transferring ofthe hot sand from one incinerator to another, and then back to the firstincinerator, a very simple and effective apparatus is provided capableof economic continuous operation. Another advantage is that the mixtureof sand and sewage travels in a general longitudinal path, and that theburners project their flames in lines parallel with said path and at theterminal end thereof, so that the hottest zone in each incinerator isadjacent to its annular internal baffle.

Having thus explained the nature of the invention and described anoperative manner of constructing and using the same, although withoutattempting to set forth all of the forms in which it may be made, or allof the forms of its use, what is claimed is:

1. A method of destroying sewage comprising intimately mixing sewagematerial with heated granular refractory material until the particles ofrefractory material are provided with coatings of colloidal sewagematerial, and completely destroying said coatings by subjecting thecoated granular material to an incinerating temperature.

2. A method of destroying sewage comprising intimately mixing sewagematerial with heated granular refractory material until the particles ofrefractory material are provided with colloidal coatings of said sewagematerial, and dehydrating and subsequently completely destroying saidcoatings by subjecting the coated granular material to a graduallyincreasing temperature.

3. A method of destroying sewage comprising heating an inorganic hightemperature-resistant material, intimately mixing sewage material withthe heated inorganic material until the particles of said inorganicmaterial are provided with coatings of said sewage material, andeffecting complete destruction of said coatings by subjecting the coatedmaterial to an incinerating temperature while traveling through a heatedspace.

4. A method of destroying sewage comprising heating an inorganic hightemperature-resistant material by causing it to travel through a heatedspace, intimately mixing sewage with said temperature-resistant materialuntil the particles of the latter are provided with coatings of saidsewage material, and completely destroying said coatings by causing thecoated temperature-resistant material to be recycled through the sameheating space, and maintaining said space at an incinerating temperatureduring such recycling.

5. A method of destroying sewage comprising heating a granularrefractory material, intimately mixing said heated granular materialwith sewage material until the particles of granular material areprovided with coatings of said sewage material, dehydrating saidcoatings by causing the coated material to pass through a heated space,and completely incinerating the dehydrated coatings by graduallyincreasing the temperature of said heated space as the granular materialapproaches the end of its travel through said space.

6. A method of destroying sewage comprising intimately mixing sewagesludge and a heated high temperature-resistant inorganic material untilthe particles of said inorganic material are provided with coatings ofsaid sewage, effecting initial dehydration and complete incineration ofsaid coatings by causing the coated material to travel toward a sourceof heat so as to increase the temperature applied to the coatings during1 travel of the temperature-resistant material through said heated zone.

'7. A method of destroying sewage comprising intimately mixing heatedgranular refractory material with sewage material until the particles ofthe granular material are provided with coatings of said sewage materialcausing said coated material to travel through a heated zone, to effectdehydration of said coatings, and increasing the temperature of theheated zone as the coated material approaches the end of its travel soas to effect complete incineration of said coatings, and subjecting thecoated material to a turbulent tumbling action during its travel throughsaid heated zone.

8. The method of destroying sewage comprising causing heated granularrefractory material to travel in succession through a plurality ofheating zones, and then recycling the same through said zones,intimately mixing sewage material with said refractory material prior toits entrance into each heating zone during the recycling stage and insuch manner as to provide the particles of refractory material withcoatings of said sewage material, and effecting complete incineration ofsaid coatings by the action of the incinerating temperature maintainedin the respective heating zones during the travel of the coatedparticles therethrough.

HENRY H. MORETON.

